to its drive motor by multiple V-belts. The vacuum producer shaft shall
have a minimum of two radial bearings and at least one support bracket.
Bearings may be permanently-lubricated sealed or lubricatable type. The
vacuum producer/connector/drive motor assembly shall be fastened to a plate
or frame structure. Power to operate the exhauster at the calculated
design load shall not exceed the normal motor rating. Power required shall
be in direct proportion to the volume of air exhausted. The vacuum
produced shall be substantially constant throughout the design operating
range of the exhauster. Vacuum producer cases shall be cylindrical in
design. Cases and end plates may be constructed of either heavy-gauge
sheet steel rigidly welded at seams or sections, or of cast grey iron.
Sheet steel end plates shall be either concave or convex for flex
resistance. Inlet connections may be axially or tangentially placed.
Exhaust connections may be tangential to the casing. Inlet and outlet
connections shall be sized to allow free air movement through the vacuum
producer, without flow restrictions. The vacuum producer shall have an
adjustable volume control device in, on, or adjacent to the first stage of
the input and an exhaust silencer on the output. The silencer and all
plumbing shall be connected to the vacuum producer flexible sleeve
connectors. Internal moving parts of the vacuum producer shall be
constructed with not less than 3.2 mm 0.125 inch clearance throughout to
prevent damage by transient particulates. Impellers shall be constructed
of built-up sheet or high tensile composites. Impellers shall be of the
backward curved design. Impellers shall be securely attached to the
exhauster shaft by set screws or clamps of high-tensile material. Each
impeller shall be individually balanced. The complete assembly with motor,
shall not exceed 0.038 mm 1-1/2 mils of vibration when given a running
test. Power to operate the vacuum producer shall be in direct proportion
to the volume of air exhausted and shall not exceed the normal motor
rating. The vacuum produced shall be substantially constant throughout the
operating range of the vacuum producer. Each vacuum producer shall have a
minimum capacity of [_____] standard cu. m per sec scfm at [_____] kPa inch
Hg vacuum at standard conditions. The vacuum producer shall be sized to
produce the above designated performance standards at the above-sea-level
elevation of the proposed installation site, and shall be so certified by
the manufacturer by equipment tag or plate, or by letter of certification
identifying the turbo-exhauster by serial number.
2.22.2.2
Motor
The motor for the vacuum producer shall be a standard NEMA MG 1, 3450 rpm,
T-frame, dripproof design; [_____] volts ac, 60 Hz, [_____] phase, with
either sealed or lubricatable bearings. Operating temperature rise of the
motor shall not exceed 22 degrees C 72 degrees F.
2.22.2.3
Isolation Pads
The vacuum producer assembly shall be mounted on resilient isolator pads as
recommended by the manufacturer. The pads shall not be fastened to the
facility floor. Vibration transmission shall be limited to less than 5
percent of the lowest frequency of vibration.
2.22.2.4
Pipe Isolators
Flexible, resilient clamped sleeves shall be furnished to isolate the
vacuum producer from associated plumbing. Sleeve couplings shall be sized
in accordance with the exhauster intake and output connections. Pipe
isolators shall be provided with steel coupling guards.
SECTION 15405A
Page 69
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